Electrically controlled units

Abstract

The invention relates to an electrically controllable machine and an electronically slip-controlled brake system having such a machine. The machine comprises an electric machine having a rotor (10), a machine shaft (18) connected to the rotor (10) in a rotationally fixed manner, and a signal transmitter (16) operated together with the rotor (10) and a sensor device for electronically detecting and evaluating the rotation angle of the machine shaft (18). The signal transmitter (16) comprises a first region (34) and a second region (32), which are arranged one after the other in an alternating manner along the circumference of the signal transmitter (16) and differ from each other in their respective electrical conductivity. According to the invention, the signal transmitter (16) comprises a sheet metal molded part, which rests flush against the rotor (10) and is anchored to the machine shaft (18) in a rotationally fixed manner.

Description

Technical Field

[0001] The invention relates to an electrically controllable machine unit.

[0002] Such assemblies are used, for example, in electronically slip-controlled brake systems of motor vehicles to actuate pressure generators. Using the supplied pressure medium, a brake pressure is built up in the wheel brakes of these brake systems, the magnitude of which is set proportionally to the volume of the supplied pressure medium. In order to calculate the displaced volume of the pressure medium, there is a sensor device that detects the rotation angle of the rotor of the electric motor of the assembly and supplies the detected rotation angle signal to an electronic control unit of the vehicle brake system for further evaluation.

[0003] Furthermore, the controller is suitable for adapting the brake pressure wheel-by-wheel to the slip ratio currently present at the respectively assigned wheel of the vehicle. This makes it possible to prevent the wheels of the vehicle from spinning, improve the driving stability of the vehicle and, ultimately, to carry out a braking process depending on the current traffic situation and independently of the current braking desire of the driver. Background Art

[0004] An electrically controllable unit is disclosed, for example, in an earlier patent application No. DE 10 2018 222 842.

[0005] The known machine comprises an electrically commutated motor having a rotor and a motor shaft connected to the rotor in a rotationally fixed manner. The rotor is designed in a conventional manner and has a rotor assembly having a plurality of magnets arranged side by side in the circumferential direction of the rotor assembly. These magnets interact in a known manner with the magnets of the stator of the motor so that the rotor is driven together with the motor shaft to perform a rotational movement. For this purpose, the stator is mounted in a motor housing, in which the rotor is rotatably supported via the motor shaft.

[0006] In order to quantitatively detect the rotational movement of the rotor, a sensor device is provided, which consists of a signal transmitter that runs together with the rotor and an associated signal receiver that is fixedly anchored on the motor housing. The signal transmitter is fixed to the rotor by mechanical connecting means, such as rivets.

[0007] The signal receiver and the signal transmitter operate according to the inductive measurement principle. To this end, the signal receiver comprises an excitation coil and a detector coil, which are alternately swept by regions of different conductivity when the signal transmitter rotates. By changing the conductivity, a variable voltage is induced in the detector coil, which controls the rotational movement of the signal transmitter or the rotor assembly.

[0008] The advantage of this arrangement of the signal transmitter directly on the rotor is the short construction of the unit in the direction of the longitudinal axis of its motor shaft. In addition, the actual rotation angle of the rotor can be detected relatively accurately, since no inertia-induced torsion of the motor shaft occurs between the signal transmitter and the rotor due to acceleration or deceleration forces acting on the rotor.

[0009] However, the printed circuit board with its wing-shaped coating is relatively expensive to produce and requires additional work steps for fastening the printed circuit board to the rotor. If rivets or screws are used as connecting means, this leads to an increase in the number of parts and an increase in the weight and moment of inertia of the rotor. Finally, when assembling the printed circuit board to the rotor, relatively high requirements must be met with regard to the concentricity of the printed circuit board relative to the longitudinal axis of the motor shaft in order not to impair the accuracy of the rotation angle detection. Summary of the invention

[0010] In contrast, the electrically controllable machine unit according to the invention has the advantage that the signal transmitter can be manufactured more cost-effectively than in the described prior art. The rotationally fixed fixing of the signal transmitter on the machine shaft can be achieved with little technical effort. Additional fixing means and work steps for anchoring the signal transmitter on the rotor are saved. According to the invention, the signal transmitter comprises a sheet metal molded part, which rests flush with the rotor and is fixed in a rotationally fixed manner on the machine shaft. Due to the flush contact of the signal transmitter on the rotor, the signal transmitter can be installed in the structural space of the electric machine and the structural length of the machine unit in the direction of the longitudinal axis of the machine shaft remains compact.

[0011] Further advantages and advantageous developments of the invention result from the preferred exemplary embodiments and / or from the following description.

[0012] In an advantageous development of the invention, the rotationally fixed fixing of the signal transmitter on the machine shaft is implemented as a press-fit connection. As a result, separate fixing means such as screws or rivets can be omitted, and the fixing process can be automatically performed and monitored.

[0013] It has proven to be particularly advantageous to implement the press-fit connection as a notched toothing. In this case, at least one notched tooth is provided in the circumferential direction of the machine shaft, protruding radially and extending in the direction of the longitudinal axis of the machine shaft, which tooth displaces material in the region of the hub of the signal transmitter when the signal transmitter is anchored on the machine shaft. As a result, a force-fitting and simultaneously form-fitting connection between the components is achieved, which particularly effectively prevents undesired relative movements between the signal transmitter and the rotor, in particular in the region of the hub of the signal transmitter.

[0014] In a particularly advantageous development of the invention, the signal transmitter is fastened to the rotor in addition to being fixed in a rotationally fixed manner to the machine shaft. This prevents relative movements or deformations of the signal transmitter in the circumferential direction and also in the direction of the longitudinal axis of the machine shaft. Otherwise, deformations could occur due to inertial forces introduced during operation-related changes in rotational speed.

[0015] For example, a friction fit can be provided between the signal transmitter and the rotor. The latter can be achieved by an elastic preload element, which is arranged on the side of the signal transmitter facing away from the rotor on the machine shaft and presses the signal transmitter against the rotor with a preload force acting in the direction of the longitudinal axis of the machine shaft. The preload element ensures that the signal transmitter rests flush against the rotor and causes friction forces between the components.

[0016] Instead of a force fit to prevent relative movements in the circumferential direction, a form fit can also be provided between the signal transmitter and the rotor. This is advantageously achieved by means of a web or a projection which is formed on the sheet metal part of the signal transmitter and projects in the direction of the longitudinal axis of the machine shaft and which engages in an associated opening in the rotor.

[0017] By plastic deformation of the ends of the tabs or projections that protrude into the openings, the signal transmitter and the rotor can advantageously be fixedly connected to one another in the sense of caulking or riveting. By means of the fixed connection, relative movements in the circumferential direction and at the same time in the direction of the longitudinal axis of the machine shaft can be largely excluded and the accuracy of the measuring results can be further increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Exemplary embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description.

[0019] The accompanying drawings include 6 figures in total, among which:

[0020] Figure 1 The rotor assembly on which the present invention is based is shown in three dimensions;

[0021] Figure 2 A machine shaft and a signal transmitter are shown, connected to each other by a conventional press-fit connection;

[0022] Figure 3 A machine shaft having notched teeth constructed thereon is shown in perspective view;

[0023] Figure 4 A preload element is shown in cross section, which presses the signal transmitter against the rotor;

[0024] Figure 5A rotor is shown with a receiving opening for a lug or a projection protruding from the cross section of the signal transmitter, and Figure 6 The webs protruding from the cross section of the signal transmitter and projecting into the openings in the rotor are shown in a schematically simplified manner.

[0025] In the various figures, the same reference numerals are used for components that correspond to one another. DETAILED DESCRIPTION

[0026] exist Figure 1 The rotors 10 of the electric machines shown in the drawings each comprise a rotor assembly 12, a plurality of magnets 14 arranged side by side along the outer circumference on the rotor assembly 12, a signal transmitter 16 of a sensor device for detecting the rotation angle of the rotor 10, which is flush with the end face of the rotor assembly 12, and a machine shaft 18, which carries the rotor assembly 12 with its magnets 14 and passes through an associated shaft passage 30 on the signal transmitter 16. The machine shaft 18 and the rotor 10 are connected to each other in a rotationally fixed manner.

[0027] The rotor stack 12 is constructed from a plurality of rotor laminations 20 stacked on top of each other and fixed to each other. These rotor laminations 20 are essentially flat, largely circular shaped parts made of a soft magnetic material, so-called electrical steel sheets. The individual rotor laminations 20 are fixed to each other, have outer contours that are congruent to each other, and are provided with continuous recesses 22 in which the magnets 14 of the rotor 10 are accommodated.

[0028] According to the present invention, according to Figure 1 The signal transmitter 16 is also designed as a sheet metal molded part. It is made of a metallic material, in particular of the same material as the rotor laminations 20 of the rotor 10, and has a plurality of recesses 32 in the region along its outer circumference, which are each separated from one another in the circumferential direction by wing-shaped sections 34. The recesses 32 form non-conductive regions of the signal transmitter 16 and the wing-shaped sections 34 form conductive regions. The recesses 32 are open, for example, toward the circumference of the sheet metal molded part; their geometry also corresponds, as far as possible, to the geometry of the wing-shaped sections 34, as an example.

[0029] Radially inwardly, an annular region with recesses 26 arranged adjacent to one another in the circumferential direction adjoins a recess 32 or a wing section 34 of the signal transmitter 16. The recess 26 surrounds a hub region 28 of the signal transmitter 16, which has a shaft passage 30 formed in the center of the hub region 28 and through which the machine shaft 18 is inserted.

[0030] According to the invention, the signal transmitter 16 rests flush against the rotor 10 and is also fixed in a rotationally fixed manner on the machine shaft 18. The rotationally fixed fixing can be implemented, for example, as a conventional press-fit connection 24. Figure 2In a first embodiment of such a press-fit connection 24, shown in FIG, the machine shaft 18 and the shaft lead-through 30 each have a cylindrical cross section in the hub region 28 of the signal transmitter 16. The outer diameter of the machine shaft 18 is measured to be larger than the inner diameter of the shaft lead-through 30 of the signal transmitter 16, so that the interference between the two components, when the components are joined together, results in a radial preload, by which the signal transmitter 16 is anchored in a rotationally fixed manner on the machine shaft 18.

[0031] In a second alternative embodiment of the press-fit connection between the signal transmitter 16 and the machine shaft 18, a notched toothing is used. Figure 3 As can be seen in FIG. 1 , for this purpose, a plurality of radially projecting notched teeth 40 are formed at regular intervals along the circumference of the machine shaft 18 and extend in the direction of the longitudinal axis L of the machine shaft 18. The notched teeth 40 extend from one end of the machine shaft 18 to the rotor 10 arranged on the machine shaft 18; the signal transmitter 16 is arranged on the machine shaft 18 in the region of these notched teeth 40. The notched teeth 40 have, at their ends facing away from the rotor 10, engaging bevels 42, through which the signal transmitter 16 is centered when engaging the machine shaft 18 via its shaft passage 30. In the region of the greatest elevation of the notched teeth 40, a gradually tapering tooth head 44 is formed, by way of example, so that the respective notched tooth 40 presses the material of the shaft passage 30 of the signal transmitter 16 during the engagement process without stripping off chips in the process. The cross-sectional shape of the notched teeth 40 can be determined specifically depending on the application.

[0032] Thus, during the phase in which the signal transmitter 16 is pressed onto the machine shaft 18, the components are relatively rigidly connected to one another by a combination of force-fit and form-fit connections. This connection is extremely robust against relative movements in the circumferential direction of the machine shaft 18, even under changing environmental conditions.

[0033] In an advantageous development of the invention, in addition to the described rotationally fixed fastening on the machine shaft 18, the signal transmitter 16 is fastened to the rotor 10. Undesired relative movements in the circumferential direction which would influence the measurement result can thereby be further counteracted. The fastening of the signal transmitter 16 to the rotor 10 can include a force fit and / or a form fit.

[0034] exist Figure 41 shows an example of a force fit between the signal transmitter 16 and the rotor 10. This force fit is achieved by means of an elastic preload element 50, which is arranged on the machine shaft 18 on the side of the signal transmitter 16 facing away from the rotor 10. Preferably, a disc spring is used as the preload element 50, which is supported on the signal transmitter 16 on the one hand and, opposite the signal transmitter, on a rolling bearing 52 which supports the machine shaft 18 in the machine housing. The distance between the rolling bearing 52 and the signal transmitter 16 is selected in this case so that the inserted preload element 50 acts on the signal transmitter 16 in the direction of the rotor core 20 of the rotor 10 with an axial force acting in the direction of the longitudinal axis L of the machine shaft 18. This axial force ensures, on the one hand, that the signal transmitter 16 is securely held in flush contact with the rotor 10 under operating conditions and, on the other hand, causes a friction force between the signal transmitter 16 and the rotor 10, which counteracts any relative movement between the components in the circumferential direction. In the example shown, the signal transmitter 16 is embodied as a three-dimensional structure with a bowl-shaped or cup-shaped cross section, but this does not exclude a flat or largely two-dimensional design of the signal transmitter 16 .

[0035] Figure 5 and 6 A variant is shown in which the signal transmitter 16 and the rotor 10 are connected to each other by a form fit. For this purpose, a tab 60 is formed on the signal transmitter 16, which tab protrudes perpendicularly to the cross section of the signal transmitter 16 and is therefore oriented coaxially with the longitudinal axis L of the machine shaft 18. The tab 60 is located on the side of the signal transmitter 16 facing the rotor 10 and can be formed, for example, by means of a U-shaped punching in the sheet metal molded part of the signal transmitter 16 and subsequently bending the inner part of the punching.

[0036] A receiving opening 64 is formed on the rotor 10, into which the web 60 is assigned or into which the web 60 extends when the signal transmitter 16 lies flush against the rotor 10. If the signal transmitter 16 is not arranged in a rotationally fixed manner on the machine shaft 18, the web 60 would thus form a driver, via which the rotational movement of the rotor 10 can be transmitted to the signal transmitter 16. Of course, a plurality of such webs 60 can be arranged distributed over the cross section of the signal transmitter 16. Figure 5 The rotor 10 is shown to be provided with a plurality of receiving openings 64 for receiving the webs 60 .

[0037] Instead of the tab 60, a projection 62 can be molded onto the signal transmitter, which projection also protrudes vertically from the cross section. Such a projection can be placed on the signal transmitter 16 by forming technology, for example, using punches and dies in stamping technology. This connection technology is also known in the professional field under the terms "clinching" or "blind rivet".

[0038] Of course, modifications or additions to the described exemplary embodiments are conceivable without departing from the basic idea of ​​the invention stated at the outset.

[0039] At this point, it should be noted that the ends of the webs 60 or the cams 62 which protrude into the openings 64 of the rotor 10 can be plastically deformed after the signal transmitter 16 has come into flush contact with the rotor 10. For this purpose, for example, a punch is introduced into the receiving opening 64 of the rotor 10 starting from the end opposite the signal transmitter 16. The free ends of the webs 60 are bent or the cams 62 are caulked axially inside the rotor 10 using the punch. In this way, a fixed connection can be formed between the signal transmitter 16 and at least one rotor lamination 20 of the rotor 10. The latter at least largely excludes radially directed relative movements, i.e. in the circumferential direction of the machine shaft 18, and axially directed relative movements, i.e. in the direction of the longitudinal axis L of the machine shaft 18, between the signal transmitter 16 and the rotor 10, and thus again enables more precise measurement results with respect to the rotation angle of the rotor 10.

Claims

1. Electrically controllable units, An electric machine having a rotor (10) which performs a rotational movement and a machine shaft (18) which is connected to the rotor (10) in a rotationally fixed manner, and a signal transmitter (16) operating together with the rotor (10) and having a sensor device for detecting the rotation angle of the rotor (10), in, A first region (32) and a second region (34) are formed on the signal transmitter (16), the first region and the second region are arranged successively in an alternating manner along the circumferential direction of the signal transmitter (16), and the first region and the second region are different from each other in terms of their electrical conductivity. It is characterized in that The signal transmitter (16) comprises a sheet metal shaped part which bears flush against the rotor (10) and is fixed in a rotationally fixed manner on the machine shaft (18).

2. The unit according to claim 1, characterized in that: The signal transmitter (16) is fixedly secured to the machine shaft (18) in a rotationally fixed manner as a press-fit connection (24).

3. The unit according to claim 2, characterized in that: The press-fit connection (24) comprises a notched tooth portion, At least one radially projecting notched tooth (40) is provided in the circumferential direction of the machine shaft (18) and extends in the direction of the longitudinal axis of the machine shaft (18), the notched tooth being designed to displace material of a wall of a shaft passage (30) of the signal transmitter (16) when the signal transmitter (16) is anchored on the machine shaft (18).

4. The unit according to any one of claims 1 to 3, It is characterized in that In addition to being fixedly secured to the machine shaft (18) for rotation, the signal transmitter (16) is also fixed to the rotor (10) by force fit and / or form fit.

5. The unit according to claim 4, It is characterized in that The force fit between the signal transmitter (16) and the rotor (10) is achieved by means of an elastic preload element (50), which is arranged on the machine shaft (18) on the side of the signal transmitter (16) facing away from the rotor (10) and presses the signal transmitter (16) toward the rotor (10) with a preload force acting in the direction of the longitudinal axis L of the machine shaft (18).

6. The unit according to claim 4, It is characterized in that The form fit between the signal transmitter (16) and the rotor (10) comprises a web (60) which is formed on a sheet metal molded part of the signal transmitter (16) and projects in the direction of the longitudinal axis L of the machine shaft (18) and which projects into an associated receiving opening (64) of the rotor (10).

7. The unit according to claim 6, It is characterized in that The end of the web (60) that projects into the receiving opening (64) is plastically deformed.

8. The unit according to claim 4, It is characterized in that The form fit between the signal transmitter (16) and the rotor (10) comprises a cam (62) which is formed on a sheet metal molded part of the signal transmitter (16) and projects in the direction of the longitudinal axis L of the machine shaft (18), and which projects into an associated receiving opening (64) of the rotor (10).

9. The unit according to claim 8, It is characterized in that The end of the projection (62) extending into the receiving opening (64) is plastically deformed.

10. The unit according to claim 1, It is characterized in that The electrically actuatable unit serves to actuate a pressure generator of an electronically slip-controlled vehicle brake system.

11. The unit according to claim 1, It is characterized in that The electric machine is an electronically commutated motor.

12. The unit according to claim 7, It is characterized in that The end of the web (60) that projects into the receiving opening (64) is bent.

13. The unit according to claim 9, It is characterized in that The end of the projection (62) that projects into the receiving opening (64) is caulked axially.

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